Method of producing SOI structures

Abstract

A method of producing so-called SOI structures according to this invention includes the step of forming an opening for seeding after an insulating layer of predetermined thickness has been formed on a first monocrystal silicon layer. Further, a non-monocrystal layer, e.g., a polycrystal silicon layer is formed on the surface of the insulating layer. The surface of the polycrystal silicon layer is smoothed as by grinding. A reflection-preventive film is formed on the smoothed surface of the polycrystal silicon layer. The reflection-preventive film has a thin film region whose reflectance is substantially zero and a thick film region having a predetermined reflectance. During laser annealing, the reflection-preventive film produces a predetermined temperature distribution in the polycrystal silicon layer. The polycrystal silicon layer which has melted according to this temperature distribution recrystallizes from adjacent the seed portion and thereby forms a new monocrystal silicon layer over the entire surface. The smoothing process for the polycrystal silicon layer prevents any change in the reflectance of the reflection-preventive film and improves control on the temperature distribution in the polycrystal silicon layer.

What is claimed is: 
     
       1. A method of producing a SOI structure with a first monocrystal semiconductor layer formed with a second monocrystal semiconductor layer with an insulating layer interposed therebetween, comprising the steps of: forming an opening in said insulating layer formed on a surface of said first monocrystal semiconductor layer, said opening reaching the surface of said first monocrystal semiconductor layer,   forming a non-monocrystal semiconductor layer in said opening and on a surface of said insulating layer,   smoothing the surface of said non-monocrystal semiconductor layer,   forming a reflection-preventive film on the smoothed surface of said non-monocrystal semiconductor layer, said reflection-preventive film having alternating first and second film thickness regions having first and second reflectances for light,   melting said non-monocrystal semiconductor layer by irradiating the surface of said reflection-preventive film with light and then cooling it for monocrystallization to form a second monocrystal semiconductor layer.   
     
     
       2. A method of producing a SOI structure according to claim 1, wherein said reflection-preventive film has a thickness such that either the first or the second film thickness region thereof has substantially zero reflectance. 
     
     
       3. A method of producing a SOI structure according to claim 1, wherein step of smoothing the surface of said polycrystal silicon layer is performed by rubbing the surface of said polycrystal silicon layer against the surface of a surface plate made of rigid material. 
     
     
       4. A method of producing a SOI structure according to claim 1, wherein after the step of smoothing the surface of said polycrystal silicon layer, an oxide film is formed on the surface of the said polycrystal silicon layer. 
     
     
       5. A method of processing a SOI structure, including an insulating layer formed on a monocrystal semiconductor layer, to produce a silicon on insulator semiconductor device, comprising the steps of: forming openings in said insulating layer at regular intervals, said openings extending from a top surface of said insulating layer through said insulating layer to the underlying monocrystal semiconductor layer;   forming a non-monocrystal semiconductor layer on said insulating layer and in said openings;   smoothing a surface of said non-monocrystal semiconductor layer;   forming a light reflection-preventive film of successively alternating first and second thickness regions along the smoothed surface of the non-monocrystal semiconductor layer, said first thickness regions having a higher light reflection capability than said second thickness regions and positioned above said openings;   irradiating the surface of said reflection-preventive film to melt said non-monocrystal semiconductor layer; and   cooling the melted layer;   whereby a second monocrystal semiconductor layer is formed.   
     
     
       6. A method of processing a SOI structure as recited in claim 5, further comprising the step of removing said reflection-preventive film subsequent to said step of cooling. 
     
     
       7. A method of producing a SOI structure with a first monocrystal semiconductor layer formed with a second monocrystal semiconductor layer with an insulating layer interposed therebetween, comprising the steps of: forming an insulating layer formed on a surface of said first monocrystal semiconductor layer,   forming a non-monocrystal semiconductor layer on a surface of said insulating layer,   smoothing the surface of said non-monocrystal semiconductor layer,   forming a reflection-preventive film on the smoothed surface of said non-monocrystal semiconductor layer, said reflection-preventive film having alternating first and second film thickness regions having first and second reflectances for light,   melting said non-monocrystal semiconductor layer by irradiating the surface of said reflection-preventive film with light and then cooling it for monocrystallization to form a second monocrystal semiconductor layer.   
     
     
       8. A method of producing a SOI structure according to claim 7, wherein said reflection-preventive film has a thickness such that either the first or the second film thickness region thereof has substantially zero reflectance. 
     
     
       9. A method of producing a SOI structure according to claim 7, wherein step of smoothing the surface of said polycrystal silicon layer is performed by rubbing the surface of said polycrystal silicon layer against the surface of a surface plate made of rigid material. 
     
     
       10. A method of producing a SOI structure according to claim 7, wherein after the step of smoothing the surface of said polycrystal silicon layer, an oxide film is formed on the surface of the said polycrystal silicon layer.